Direction sensing device



Oct. 20, 1953 3, MAY 2,655,938

DIRECTION SENSING DEVICE Filed July 26, 1949 72 was 2o 1 T 27 12-s\1o119 2o 15 9 11107512 15 ruJOr I erse Engine Crank Shofi JNVENTOR.

y Harry 0. May

A 7' TOPNE Y Patented Oct. 20, i953 DIRECTION SENSING DEVICE Harry 0. May, East McKee'spoft, Pa", assignor to Westinghouse Air Brake Company, a corpora tion of Pennsylvania Application July 26, 1949, Serial No. 106,863

'4 Claims. (Cl. 137-609) This invention relates to a direction sensing device and more particularly to such a device for use as a directional interlock valve device in reversible engine control apparatus.

The principal object of the present invention is the provision of an improved directional interlock valve device of the type disclosed in United States Patent No. 2,459,883, issued to Cecil S. Kelley on January 25, 1949.

The above-mentioned patent discloses a di rectional interlock valve device which comprises valve means adapted to be actuated to either one of two positions for connecting a delivery pipe to either one or the other of two control pipes. respectively. The valve means is actuated. through certain linkage by movementof a shoe in frictional engagement with such as an engine crank shaft in rotation to position said valve means in either of two positions according to the direction of such rotation. A fluid pressure piston is provided for moving the shoe intoengagement with the shaft, and a return spring is provided for returning said shoe and piston to respective repose positions. For locking the valve means in either of the two positions, a pin se cured to the casing of the device projects into one or the other of twospaced apart recesses formed in a rib of the shoe when same assumes its repose position. Contingent upon severe vibration, the shoe may bounce free of the locking pin and allow the valve means to assume an undesired neutral position. In view of this, it is another object of the invention to provide a directional interlock valve device which comprises improved means for locking the valve means in position.

A further object of the invention is the provision of means to limit the force exerted by the shoe on the shaft when held in Contact therewith by the piston.

A still further object of the invention is to provide an arrangement whereby sudden undesired pressure impulses of short duration which may get into the pipe which conveys working fluid to and from the fluid pressure shoe actuating piston, are prevented from causing accidental operation of said piston.

Other objects and advantages will become apparent from the following detailed description 01? the invention.

In the accompanying drawin the single figure is a sectional view of a directional interlock valve device, embodying the invention.

Description Referring to the drawing, the directional 66h trol device comprises a casing I having two op= positely arranged, coaxially aligned val've as= semblages 2 and 3 for controlling communic a tion respectively, between a delivery pipe i and control pipe 5, 6.

Both of the valve assemblages 2 and 3 may be alike, and for sake of brevity, identical elements of the two assemblages will be given the same reference numerals in the drawing, with the reference numerals pertaining to the elements of assemblage 3 primed to distinguish over the elements of assemblage 2 to avoid confusion subsequent description of operation of the device.

For sake of illustration, schematically,- the valve" assemblages 2 and 3 may com rise respectively, a poppet valve I, I disposed in a chamber 8, 8 formed in the casing I. The poppet valve '1, 1' is attached to an actuating stern 9, 9' which is slidably disposed in a casing here it, |0 through the medium of a connecting stein H; H. A valve Seat is formed ill the casing Gil circling one end of the bore m, in to accommodate the valve '1, 1' which, when seated thereon, closes the chamber 8, 8" to said bore. A coinpress-ion spring l2, i2 is disposed in the chamber 8, 8' and arranged to urge the valve 1, 1' toward its seat. A removable cap I3, l3 iii screwthreaded attachment with the casing is provided to retain the spring l2, 1; and to anew for movaI and insertion of the valve 1, 1' and at tached stems 9, 9 and ll, ll. Ihe stem 9, 9 projects outwardly through the opposite eiid of the bore If] for engagement witli an actuating element l5 slidably mounted in the casing.

In the assemblage 2, the chamber 8' is connected to the forward control pipe 5 and the bore 10 is constantly open to the bore H1 in as: semblage 3 and to the delivery pipe 4 by way of such as a passage 4a formed in the casing. In the assemblage 3', its chamber 8' is connected to the reverse control pipe 6.

When the actuating element 15 is moved in" the direction of the ass'mmage 2, the stem 9' will be displad inwardly 6f the bof' III;- ahd incl-@133 cause unseating of the poppet valve 1 against action of the spring I 2 and opening the chamber 8, hence the control pipe 5, to the bore Ill, hence to the delivery pipe 4. At the same time, such movement of the element I5 will allow, in assemblage 3, the spring I2 to seat the poppet valve 1' thereby closing off the bore hence delivery pipe 4, from the chamber 8', hence from the control pipe 6. Upon return movement of the actuating element [5 in the direction of the valve assemblage 3 to the position in which it is shown in the drawing, through resultant movement of the stem 9', the poppet valve 1' will be moved to its open position in which it is shown in the drawing, thereby opening the chamber 8, hence the control pipe 6, to the bore l0, hence to the delivery pipe 4. At the same time such movement of element IE will, in valve assemblage 2, allow the spring 12 to move the poppet valve 1 to its closed position in which it is shown in the drawing, thus closing ofi the chamber 8, hence the control pipe 5, from the bore I0, hence from the delivery pipe 4. Openings in the casing are provided for slidably guiding the actuating element l5.

To sense the direction of rotation of such as reversible engine crank shaft 25, for example, a friction shoe assemblage 26 is provided. The shoe assemblage 26 may be moved into engagement with the shaft 25, which, when in rotation will urge the shoe assemblage either toward the valve assemblage 2 or toward the valve assemblage 3, according to the direction of such rotation.

The shoe assemblage 26 is loosely connected at 21 to one end of an operating stem 23 which is rockably connected at its opposite end to a shoe actuating piston assemblage 29 to allow for sidewise movement of the friction shoe assemblage when in engagement with the rotating engine 1 crank shaft 25. To define the limit for such sidewise movement, the shoe assemblage 26 may engage either one of two spaced apart casing shoulders 35, 36 according to the direction of the movement. The stem 28 extends through an opening defined by a rounded shoulder 31 formed in the actuating element l5, thereby operatively connecting the shoe assemblage 25 to said actuating element. During sidewise movement of the shoe assemblage 26, resultant rocking movement of the stem 28 is translated into sliding movement of the actuating element l5 through engagement of said stem with the rounded shoulder 31. When the shoe assemblage 26 is in position in engagement with the shoulder 35, the actuating element IE will be in the position in which it is shown in the drawing, holding the poppet valve 1' unseated against action of the spring l2, with the poppet valve 1 seated. Conversely, when the shoe assemblage 26 is in position in engagement with the opposite shoulder 36, the actuating element will be in a position opposite to that in which it is shown in the drawing, holding the poppet valve 1 unseated against action of the spring I2, with the poppet valve 1' seated.

To hold the actuating element l5, and thereby the stem 28 and shoe assemblage 25 in one or the other of their corresponding opposite positions described, above, an improved locking means is provided which comprises a tapered locking pin 4!! reciprocably fitting in an accommodating casing bore 4| for slidable engagement with a similarly tapered locking element 42 attached to and carried by the actuating element l5. When the actuating element l5 assumes the position in Lil which it is shown in the drawing, it may be locked therein through engagement between coincident faces 43, 44 of the tapered locking pin 4!) and element 42, respectively. When the actuating element l5 assumes the position opposite to that in which it is shown in the drawing it may be locked in such position through engagement of opposite faces 45, 4B of stem and element 42, respectively. The stem 40 is urged into locking engagement with the element 42 by a compression spring 41 disposed in an atmospheric chamber 48 at one side of an unlocking piston 49 attached to said stem. The tapered faces 43, 45 and 44, 46 of stem 40 and element 42 respectively, act to urge the actuating element 15 toward the position in which it is desired to lock same when said pin is urged by spring 41 into engagement with said element 42. The unlocking piston 49 is slidable within an accommodating bore 50 in the casing. Upon supply of fluid under pressure to a chamber 5| at one side of the piston 50, said piston may be caused to move in the direction of chamber 48 against action of the spring 41 to move the stem 40 out of locking engagement with the element 42, thereby freeing the actuating element for slidable movement. Upon subsequent release of fiuid under pressure from the chamber 5|, the spring 41 will return the piston 49 to the position in which it is shown in the drawing, defined by contact with an annular seat rib 53, thereby movin the stem 40 into locking engagement with the element 42. One purpose of the seat rib 53 is to reduce the effective area which will be exposed to the pressure of fluid in the chamber 5| when the piston 49 is seated thereon, so that when once unseated, the increased area thereby presented to such pressure will cause snap acting movement of the piston to an opposite position in engagement with an annular resilient seat washer 55, thereby quickly unlocking the actuating element I5 to prevent drag between the stem 40 and element 42 and thereby prevent excessive wear on these parts. An operating control pipe is connected to the chamber 5| for conveying fluid under pressure thereto and therefrom.

The piston assemblage 29 may comprise a piston follower element 10 which is slidably mounted in a suitable bore 1| in the casing. The stem 28 is slidably and rockably connected at its one end to the follower element 10 through the medium of an attached disk-shaped element 12 slidably disposed within an accommodating bore 13 opening into said element 10 centrally thereof. The element 12 is retained in the bore 13 by a retaining ring 14, which is removably secured to the follower element 10. The element 12 is provided with a radius about its periphery in slidable line contact with the wall of the bore 13 to allow for pivotal movement of the respective end of the stem 28 during sidewise movement of the shoe assemblage 26 at the opposite end of said stem. The end of the stem which is attached to the element 12 is of reduced cross section for projection through the retaining ring with clearance to allow for the above mentioned pivotal movement. A compression spring 15 is arranged to seat at its one end against the piston follower element 10, an annular groove 16 being formed in said element 10 to locate the respective end of said spring. The opposite end of the spring 15 seats on a spring seat washer member 18 carried by the stem 28, an annular collar 19 being formed member 18 is urged by said spring. The spring 15 urges the stem 28 in a direction away from the follower element 10 and toward the crank shaft 25. In the. position of the piston follower element 29 shown, the element '52 of the. stem. 28: is in engagement with the retaining ring '14, thereby defining a repose position of. the shoe assemblage 26 spaced away from. the crankshaft. The piston follower element in is urged toward the position in which it is shown in the drawing by a piston return spring 8%} compressed between said element 70 and an. annular shoulder 81 formed in the. casing The piston. assemblage 29 further comprises a resilient diaphragm 85. which is. clamped at its outer periphery between two portions of the casing. The diaphragm 815 is exposed to a pressure chamber St on its one face while its opposite face fits against a face of the piston follower element which is properly contoured, to accommodate the usual annular fold at the outer. edge: of the diaphragm which allows for movement of said follower element by said diaphragm when fluid under pressure is supplied to said. chamber 86..- Movement of the follower element 10 out of its. repose position, in which it is. shown. in the drawing and which may be defined by contact of a central portion of the diaphragm with an end wall 9! of the casing, in the direction of the crank shaft is limited by engagement with an annular shoulder 9| formed. in. the casing. The presure chamber as at the one. side of the diaphragm 85 is connected to a casing port and passage 52 which opens at its one end into the bore 50 in which the unlocking piston 49 is slidably disposed. The port 92' is solocated that, with the unlocking piston. in the position in which it is. shown in the drawing, that is, seated on the. rib 53., said port 92 will bein registry with a port and passage 95 extending through said piston from its peripheral edge to the atmospheric chamber. 48 at its one side. Said port: 92: will be opened to. the chamber EH when said piston, leaves said rib and seats on the resilient seat washer 55.

Operation Referring to the drawing, assume that the directional interlock device was last operated when the engine crank shaft was turning in its forward direction withv the operating control pipe Bllnow vented.v All parts of the directionalinterlock device will have assumed the respective positions. in which they are shown in the draw- 7 ing. Fluid. under. presure will. have vented from the pressure chamber 86 by way of" they Passage 92, chamber 5lj and the pipe (ill. The piston fol.- lower element lfi' will be. inv its repose. position, with the diaphragm 8.5 seated against the casing end. wall 90, and the unlocking piston 49 will be seated on rib. 53- The locking stem All will be inlocking engagement with the element 42*,ho1ding; the actuating element ['5 in position to maintain the valve 1 open, the valve T closed, and holding the shoe assemblage 26' in leaning engagement with casing shoulder 35. The element i2 attached to the end of the stem 28' will be seated on the retaining ring M attached to fol.- lower element 10, and the shoe assemblage 26' will be disposed a short distance away from. the engine crank shaft 25.

Assume now that the engine crank shaft 25 is again rotating its original or forward direc' tion, when. the directional interlock device is brought into operation- Fluid will be supplied to the chamber 5i beneath the unlocking piston 49-, and when the pressure of such fluid increases sufficiently, will cause said unlocking piston to.

snap to. itsopposite position seated on. washer 55,.

6? to unlock the actuating element l5; Fluid under pressure will flow fromthe chamber 51 through the passage 92 to the pressure chamber 86, cans-'- ing deflection of the diaphragm 85 and resultant movement of the follower element 10 out ofits reposeposition to its. position in engagement with the shoulder 91. This movement of the follower element l0 out of its repose position will carry the compression spring 15' and stem 28 with it and thereby will cause engagement of the shoe:

assemblage 26 with the forwardly rotating crank shaft 25, and will cause the force of the precompressed spring 15 to be transmitted through the stem 28 and said shoe assemblage to said crank shaft as the element 12' of said stem is caused to unseat from the-retaining ring 14 and follower element la engages the casing shoulder" 9|. 7 It will be appreciated that the force exerted by the shoe assemblage 26 against the crank shaft 25 will be limited substantially to that resulting from the compression of the spring [5; and such force will be constant and independent of the pressure of fluid which may be supplied to the chamber 85' for effecting movement of said shoe assemblageintoengagement with said shaft.

Since the shaft 25 is turning in its original or forward direction at this time, the shoe assemblage 26 will remain in engagement with the casing shoulder as, and the actuating elementf5 therefore will remain so positioned as tomaintain the valve T open and the valve 1 closed, with the delivery pipe 4' consequently connected to thecontrol pipe 6 and disconnected from the con trol pipe 5.

If, while the shoe assemblage 26 isthus in. engagement with theforwardly rotating engine crank shaft 25, the pipe isvented to atmos phere; the unlocking piston 49 will be moved to its seated position on therib 53- by action of the spring 41 as pressure of fluid is reduced in the chamber 5! through release-of fluid underpressure by way of the vented pipe 692 'I'helocki'ng stem 4% thus will be moved to its positionfor locking the actuating element i5. and valves I 1" in the position described. above. When the unlocking piston 49 assumes its position seated on rib 53, theport and passage 95 in said piston willbe brought into registry with the port or passage 92, allowing fluid under pressure from the pressure chamber 85= to release to atmosphere by way of the atmospheric chamber 48 at one side of said piston 49'. The shoe assemblage. 263 will thenbe carried to its retracted position disposed away from the crank. shaft 25. as: the diaphragzrr 8'5, follower element it, spring T5. and stcm'm are caused by spring to assume the. positions:-

in which they are shown in the drawing and in. which. they were; previously described.

Assume that: the shoe assemblage 2a is: in one gagement with the forwardly rotating. shaft 25,.

with the chamber 86 charged. with fluid: under. pressure'and the. actuating; element 5 unlocked as previously described Assume that. while the shoe assemblage is in engagement with the shaft 25, the shaft reverses its direction. of rotation.' from forward to reverse, for example. Upon v initial; turning movement of the shaft 25-v in. its new or reverse direction, the shoe assemblage 26. will leave the shoulder 35 and move into engagement with the-shoulder 35,. causing movement of the actuating stem is to its position for: allowing the valve S ta close and to open the valve 1,, thereby connecting the delivery pipe 4 to the control pipe 5 rather than to the control pipe 6.. If.

at this time. the. pipe 60.- is vented, the unlocking piston will move to cause locking of the actuating stem and valves as previously described, followed by return of the follower element 10, stem 28 and shoe assemblage to their respective repose positions as fluid under pressure releases from the chamber 86 by way of the passage 92, port 95 in the unlocking piston 49, and the atmospheric chamber 48 at one side of said piston.

The interlock valve device may again be brought into operation as aforedescribed to sense the direction of rotation of the crank shaft 25 and cause positioning of the valves 1, 1 accordingly, and subsequently released as described, with the crank shaft turning initially in its reverse direction and reversing its direction of rotation back to ahead during engagement of the shoe assemblage 26 therewith in fashionsimilar to operation as described.

Summary It will be appreciated that I have provided a directional interlock valve device which comprises improved means for locking the actuating element I and valves '1, I in their adjusted positions which will not be influenced by engine vibrations or the like and will maintain such positions reliably.

It will also be seen that by virtue of the fact that supply of fluid under pressure to the pressure chamber 86 is controlled by operation of the unlocking piston 49, sudden undesired pressure impulses which may leak into the pipe 60 will not cause unintentional engagement of the shoe assemblage with the shaft, since such pressure impulses, being exerted against a limited area of the piston 49 when seated on rib 53 will not produce a force sufficient to unseat said piston and allow a supply of fluid under pressure to reach the pressure chamber 86.

And still further, it will be appreciated that by virtue of the arrangement for effecting engagement of the shoe assemblage with the shaft 25, through transfer of force resultant from the precompressed spring 15, the force of said shoe on said shaft may be kept at a desired minimum and a constant value, regardless of the pressure of fluid which might be supplied to the chamber 86.

Having now described the invention, what I claim as new and desire to secure by Letters Patent, is:

1. In combination with a casing having a first chamber and a second chamber, a motion reversible member, a structure movable longitudinally into and out of engagement with said member and movable transversely by said member when in engagement therewith, actuating means responsive to supply of fluid under pressure to said first chamber to effect longitudinal movement of said structure into engagement with said member, first spring means to effect longitudinal movement of said structure out of engagement with said member upon release of fluid under pressure from said first chamber, a valve actuating element slidably mounted in said casing and operably connected to said structure for slidable movement thereby in one direction or its opposite according to direction of transverse movement of said structure, valve means operable by said valve actuating element to assume positions according to direction of sliding movement of said actuating element, stop means engageable by said structure to define two opposite positions of said actuating element, a locking pin movable into engagement with said actuating element to lock same in either one or the'other of its opposite positions, unlocking piston means operatively connected to said locking pin responsive to supply of fluid under pressure to said second chamber to disengage said locking pin from said actuating element and to uncover a port connecting said first chamber to said second chamber, and second spring means cooperative with said casing and said unlocking piston to urge said unlocking piston in the direction of said second chamber to cause engagement of said locking pin with said actuating element and to open said port to atmosphere for releasing fluid under pressure from said first chamber.

2. The combination as set forth in claim 1, including other spring means interposed between said structure and said actuating means through the medium of which the longitudinal movement of the former is effected by the latter.

3. In combination, a reversible rotatable shaft, a casing having a pressure chamber, a passage connected to said pressure chamber and a piston bore arranged radially to said shaft, a friction shoe for engaging said shaft, a piston disposed in said bore for slidable movement therein, a stem carrying said shoe at its one end and having a pivotal connection with said piston, said pivotal connection being slidable longitudinally of said piston, a spring seat element carried by said stem intermediate its opposite ends, a first compression spring abutting at its one end said piston and at its opposite end said spring seat element, urging said stem in a direction away from said piston and toward said shaft, retaining means cooperable between said piston and said stem, a second compression spring cooperable with said casing and piston for urging said piston in a direction away from said shaft to a repose position in which said stem is in engagement with said retaining means and said friction shoe is disposed a certain distance away from said shaft, means for defining said repose position, flexible diaphragm means operable in response to supply of fluid under pressure to said pressure chamber to overcome action of said second compression spring for effecting slidable movement of said piston to a shoe engaging position in which said friction shoe is held in engagement with said shaft by force of said first compression spring, stop means cooperable with said piston to define said shoe engaging position, two oppositely arranged valve structures disposed in said casing at opposite sides of said stem, a rigid valve actuating element interposed between said valve structures and slidably movable by pivotal movement of said stem to one or the other of two opposite positions to condition said valve structures accordingly, a locking stem movable into engagement with said actuating element for looking same in one or the other of said two opposite positions, third spring means urging said stem into such engagement, and unlocking piston means operatively connected to said locking stem and operable to move said locking stem in opposition to action of said third spring means for disengaging said locking stem from said actuating element, movement of said unlocking piston means in cooperation with said passage also controlling supply and release of fluid under pressure to and from said pressure chamber.

4. In combination with a casing having a first fluid pressure chamber, and a second fluid pressure chamber, a motion reversible member, structure movable longitudinally into engagement with said member and movable by such engagement to either of two opposite transverse positions, first fluid pressure actuating means responsive to supply of fluid under pressure to said first fluid pressure chamber to move said structure longitudinally, a locking pin in locking engagement with said structure preventing transverse movement of same, second actuating means operatively connected to said locking pin and responsive to supply of fluid under pressure to said 1 second fluid pressure chamber to move said locking pin to a position out of locking engagement with said structure, and valve means associated with said second actuating means controlling ad- 10 mittance and release of fluid under pressure to and from said first fluid pressure chamber.

, HARRY C. MAY.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 2,197,292 Brady Apr. 16, 1940 2,459,883 Kelley Jan. 25, 1949 2,593,604 Price Apr. 22, 1952 FOREIGN PATENTS Number Country Date 541,445 France of 1922 

